Refactored QGC::groundTime*() functions to be simpler.
Merge pull request #695 from Susurrus/time_fix

Refactored QGC::groundTime*() functions to be simpler.
Fix for #647.
In the logplayer, the data stream is read ahead for messages, which is used to determine the size of the output bytearrays. Previously, this wasn't done correctly resulting in non-ideal behavior. Now, the next message is scanned properly, so the only bytearrays that are emitted from QGCMAVLinkLogPlayer are MAVLink messages in their entirety. This also has the benefit of skipping invalid/corrupted messages in the log that's being played back.
Removed constant debugging output from scanning for serial ports.
Replaced with only 1 output message with the result of the first serial port scan.
Add documentation for setupPortList() now that I modified it.
Merge pull request #696 from Susurrus/fix_647

Fix for #647
Merge pull request #697 from Susurrus/serialport

Removed constant debugging output from scanning for serial ports.
Replaced hard-coded severity values with proper MAV_SEVERITY_* macros.
Merge pull request #700 from Susurrus/mav_sev

Replaced hard-coded severity values with proper MAV_SEVERITY_* macros.